As megapixel counts grow and pixel dimensions shrink in the field of digital imaging, longer exposure integration times may be required for a given brightness of scene lighting. However, if an exposure is too long, camera motion may result in a blurred photograph.
A camera or other image capture device may measure available light and conservatively decrease exposure times in an attempt to reduce blur due to camera motion, motion in the scene, or both. The imaging device may increase a lens aperture diameter to compensate for the reduced exposure time, resulting in a shorter depth of field. An out-of-focus image may be captured as a result.
In low light conditions, the camera may reach the wide extreme of the available aperture adjustment range without reaching an exposure time sufficiently short to avoid a blurred image according to the conservative exposure algorithms in common use. Under such conditions the camera may risk blur by increasing the exposure time. Alternatively, a dark image may be captured, possibly resulting in an unacceptable level of pixel noise. As a third alternative, the camera may simply disable image capture under such low light conditions. Thus, a need exists for a more refined approach to exposure setting adjustment to avoid blurred images due to relative movement between an image capture device and a scene to be captured.